1. Field of the Invention
This invention relates to an over-voltage protection apparatus. Also, this invention relates to a vehicular direction indicating apparatus with over-voltage protection.
2. Description of the Related Art
In a general power feed system, a load drive switch is interposed in a power feed line connected between a power supply and a load. It is known to provide such a power feed system with an over-voltage protection device. The known over-voltage protection device has a section for detecting an over-voltage induced at the power feed line by one of various causes. When such an over-voltage is detected, the known over-voltage protection device forces the load drive switch into its conductive state to allow the escape of the over-voltage toward the load.
In the case where the load is a vehicular direction indicator having a very small impedance, when the load drive switch is forced into its conductive state in response to an over-voltage, the voltage at the power feed line abruptly drops. The abrupt drop in the voltage returns the load drive switch to its non-conductive state. The return of the load drive switch to its non-conductive state tends to cause an over-voltage again due to the inductance of the power feed line. As a result, the load drive switch oscillates between its conductive state and its non-conductive state. In other words, the load drive switch chatters.